What good light brings us
The wrong light at the wrong time may result in mood disturbances, sleep problems, difficulties with learning and memory, and health problems on the long term as well as of course problems with vision on the short term. While this might be a problem for all people living and working indoors, it is in particularly bad for people already suffering from sleep- and mood disorders, such as depression, or brain problems, such as dementia. It is estimated that about 13% of the global population suffer from some kind of mental disorder. A simple improvement of the light environment may be beneficial for all of us, but for this group in particular.
Good light is essential for a properly synchronized biological clock, responsible for our day-night rhythm, and it improves our sleep.
Good light makes us feel energetic, alert, and concentrated.
Good light makes us feel welcome, relaxed, safe, cozy and happy.
Good light supports our vision; it shows us objects, colours, contrasts, and motion.
What is good light
Good light is the right light at the right time and in accordance to our activity and our personal needs during every day of our life. Good light is natural light, or indoor light mimicking natural light as much as possible.
For lighting experts:
Good light is Attractive
Good light indoors is high quality and comfortable for the eyes.
High quality means that the lighting system provides good colours (rendering and preference), low glare, no temporal light artifacts (flicker and stroboscopic effects), attractive contrast differences and distribution of light in the environment, no audible noise and being safe.
Good light is Dynamic
Good light indoors is stimulating during the day with an intensity that is at least 5x higher and relaxing during the evening with an intensity that is at least 5x lower, than the current standard for vision.
With aging, from 50 years onwards, higher intensities are usually needed to support visual and non-visual needs. In case of shiftwork or work in evening/night or work at irregular times, deviations from these guidelines are needed. Horizontal and vertical light levels need to be adequate for both visual and non-visual effects.
Good light is Optimized
Good light indoors has spectral characteristics that vary according to time of day, personal needs, and specific tasks.
In the morning and during daytime, the light spectrum should include a reasonable portion of short wavelengths to support the energizing and revitalizing effects of light. In the evening and at night, the amount of short wavelengths should be diminished to support winding down, a good night of sleep and to prevent disruptions of the day-night rhythm. With aging, from 50 years onwards, the need for spectral characteristics may change because of a change in lens characteristics. In case of shiftwork or work in evening/night or work at irregular times, deviations from these guidelines are needed.
Good light is Personal
Good light indoors can be adapted by the user for personal needs based on suggestions by the system. Individuals may differ in light appreciation with respect to intensities and preference for warm or cool white light. In addition, individuals differ in the phase of their sleep-wake rhythm, also referred to as being a different chronotype. This results in individual differences in the most optimal timing of the dynamic pattern of light, both with respect to intensity and spectral characteristics. Personal control over the dynamics and spectral characteristics of light is highly appreciated by individuals.
to energize is daytime light that makes us feel active, alert and concentrated
to wake up is morning light that wakes us up feeling energetic and happy without suffering from sleep inertia
to work is daytime light of suiting the demands of work and keeping us active and concentrated
to learn is daytime light that support learning and memory
to relax is light for certain moments of the day where we need to rest and relax
to sleep is high intensities of light during daytime and low intensities of light during the evening and at night, both with certain spectral characteristics, to support a consolidated sleep
for well-being is the right light at the right time with an intensity and with spectral characteristics supporting wakefulness during the day and sleep during the night improving long term health and well-being